Log in.
In this instance, you have a post visible so you can go to the “deeper dive” step, below.
Otherwise, when you can’t call up any of your old posts, type your screen name (not your username) into the “Search Forums” box near the top of the Forum page. That will bring up some of your recent posts.
For a deeper dive, then click of your screen name at the left of one of your posts and that will take you to your profile where you will see “Topics started” and “Replies Posted” on the left and you can click on them to get to those posts.