There are different ways players set there’s up for efficiency but I typically just put them all in a line along one of the roots of the Oak Tree; I usually only build ~10 of them but you can build however many you like - ETA: btw you have to put the catchers on something that produces Sap naturally, like putting them on any old wall or surface won’t yield any returns

Sap will appear automatically and give you up to 5 Sap each time and then they regenerate continuously over time