Achievement progress can be added/updated from the individual Sim’s page, or the specific progress category pages.
If updating from a specific sim’s page, start by selecting the Sim under the Currently Playing section.
Scroll down to the achievements checklist. Use the tabs to filter through different categories. Find the item that you want to check off and hover to the right, then click the pencil icon.
When you click on the pencil, fields will pop up to add your Sim and the date. When you click “Add Sims”, a list of all sims you have entered will pop up. When you select date a calendar will pop up. Select the Sim and the date completed, then check off the box to the left.
To update via achievement pages, scroll down on the home page to the Achievement Tracker pages, and select whichever category you are updating.
This will bring you to the specific achievement pages. There will also be links to relevant pages on the Sims Wiki at the top right for more info. Scroll down to the specific category that you want to check off.
Find the specific item, hover over the box and select the pencil. Choose your sim from the drop down and the date completed, then check of the “Complete” checkbox. (Note: sometimes a field will pop up for “additional info”, you don’t need to enter anything there)