According to research, this docking station is not compatible.

According to my information, the Ideapad 720s-15 does not offer an Onelink+ port. I recommend a Thunderbolt 3 or USB 3.0 docking station.

The docking station has only one onelink output, the yellow plug does not fit!

Yes, because the "Lenovo ThinkPad 13" and the "Lenovo ThinkPad 13 G2" have the matching "OneLink+" connection. The notebook is also supplied with power and charged via the "OneLink+" connection. Please note that one of your two screens must have a DisplayPort connection because the docking station provides 2x DisplayPort and 1x VGA. (if both screens have a DisplayPort connection, then that is of course even better...)

Unfortunately I can't answer this question because I only work with Wodows, please ask Lenovo directly.