Prerequisites

Ensure you are an admin of your Workday account before starting.

Log into Workday
Search for "View API Clients"
If you can not see this menu item, you are not an admin of the Workday account.
If you do not see this menu item, figure out who your Workday Admin is and ask them to give your account sufficient permissions or to take over the integration process.

Create an integration system user (ISU)

Click on the "Search" field at the top and enter "Create Integration System User"
Click on the task "Create Integration System User" that just appeared
In the dialog that just opened, enter a username and generate a secure password.
You can leave the other fields untouched
At the bottom of the dialog, click "OK"

Add the ISU to your list of system users

While the newly created ISU will work for linking your Workday account its password will expire after some time unless you add it to your list of system users.

Create a security group and assign the ISU to it

Click on the "Search" field at the top and enter "Create Security Group"
Click the task "Create Security Group" that just appeared
On the page that just appeared locate the dropdown "Type of Tenanted Security Group" and select "Integration System Security Group (Unconstrained)"
For the "Name" enter the value of the "User Name" when creating the ISU earlier (in this case it would be test_isu, but yours will be different)
At the bottom of the page, click "OK"
On the next page, the only thing you have to do is go to the field "Integration System Users" and add the user you created earlier. You can do this by clicking on the field and typing in the name of the ISU (in this case test_isu)

After that, go ahead and click "OK"

Add the required permissions to the security group

Click on the "Search" field at the top and enter "Maintain Permission for Security Group"
Click on the task "Maintain Permission for Security Group" that just appeared
In the window that just appeared, make sure you have the option "Maintain" selected
Click the field "Source Security Group", enter the name of the group (in this case test_isu) and hit enter. Then click on the security group to select it.
Click "OK"
Add the Domain Security Policy: "Worker Data: Current Staffing Information" with "Get Only" access:
Click on Done at the bottom

Activate your changes

After making any changes to your Workday security policy settings, make sure to apply those changes by executing the "Activate Pending Security Policy Changes" task. Without that, none of your changes with take effect.

Click on the "Search" field at the top and enter "Activate Pending Security Policy Changes"
Click on the task "Activate Pending Security Policy Changes" that just appeared
In the window that just appeared, add any comment for applying the changes (i.e. "Grant ISU test_isu necesssary permissions for integratons"
Click "OK"
In the new window, check the box "Confirm"
Click "OK"

How to create a ( webservice ) custom report?

Find the right Task to Create Custom Report
Give your report a descriptive name
Choose Advanced as your Report Type
Enable it as a Web Service so we can access it later
Disable the optimization toggle so we can explore more fields
Search for “All workers” and press enter
Verify your settings
Create your report by pressing OK
You should get redirected to the Edit Custom Report page

How to setup the custom report?

Optional: Open the custom report to edit it

Search for Edit Custom Report
Find the custom report you want to edit in the context menu
Press OK to open the custom report

The basics ( tables, search )

In the view you open you will find two tables.
In the first one you will be setting up the basic fields of the report. We will refer to it as the Business Object Table
You can easily find any business object and field by searching it. To search it first enter the value and then confirm your search and press enter.
This search works for every Field and Business Object in the report and will help you set it up quickly.
We will call the table at the bottom the Overrides Table

Business objects table

Now you can open the connection flow and check which fields are required in your report:
For every required field, please find the correct Business Object, Field and based on our guidelines enter the correct Column Heading Override XML Alias.
The complete Business Object Table would look like in the image below given the fields described in the connection flow:

Overrides table

Once you finished the Business Object Table you will have to map some fields from other entities
The final table would in this case look like this: