Read the paint conditioner instructions carefully, noting the recommended amount of conditioner compared to paint. Mix a small amount of conditioner and paint together in a disposable cup based on the conditioner's ratio recommendations. Stir with the stir stick.
Spread the conditioner/paint mixture on a scrap piece of cardboard, using a paintbrush to test for compatibility and drying time. Note how long it takes to dry.
Mix a larger quantity of conditioner and paint in a container with an airtight lid. Use the same ratio as you did with the test batch, or adjust it slightly if necessary, staying within the recommended conditioner to paint ratios. Stir with a stir stick. Replace the lids on the conditioner and the latex paint.
Paint your project with the conditioner/paint mixture. When you're finished, replace the lid of the mixture's container to save it for another painting session.