In qigong, on the inhale you gather qi, on the exhale you compress qi into lower dan tian. It’s on every breath.
After doing 9, 18 or 36 breaths like that, then I focus on the microcosmic orbit or other exercise that I wanted to do with the qi. You can also experiment with gathering it to middle and upper dan tians, the latter beig the standard 3rd eye meditation, but too much of that can make you imbalanced and give you a headache, if you store in the lower dan tian first and move it from there that’s very safe.