Hi @S2_045
Here you go:
1.Go to admin center, select the appropriate environment and click on 'All legacy settings':

You will be redirected to "Business Management" setting page, https://<<Environment URL>>/main.aspx?settingsonly=true#27557030
You can directly navigate to classic setting page by replacing the environment url.
2. Next, click on Settings and Processes under 'Process Center' section:

3. Now, click on 'New' and fill the required details like name, category and select the process entity, here my business process name is 'RFQ BPF' so I have selected the same in the Entity dropdown and click on Ok button to proceed:

4. Next, check the 'Process change' checkbox and click on 'Select' button:

5. Now, Select the record type and check the 'Technical Proposal Completion' field, click 'OK; button:

6. Next, click on 'Add action' and select 'Check condition' from the sub menu:

7. Give the step name and click on add condition to configure link:

8. Configure the condition and click 'Save and close button'

9. Now, select the row and add a new step by selecting 'Update Record' from sub menu:

10. Now, enter the step name & select the entity to update. click on 'Set properties' button:

11. Select the Active stage (next stage) and click 'save and close' button:

12. Click on "Activate" to activate the process:

Finally, close the process and test it using from the Model driven app.
When i changed the status of 'Technical proposal completion' field to 'Completed' the workflow runs in the background and update the business process stage:

After refreshing the record, you will see the updated stage:

If this helps, please remember to give a 👍 and accept my solution as it will help others in the future.
Thanks