The following tips are not requirements for assembly, but they may make the assembly process easier for you.

No tools are required but using a rubber mallet to drive the legs into the sockets may be helpful.
Spraying the sockets on the panels and or the bottom of the legs with a common glass cleaner before inserting the legs allow for easier assembly as well.
Make sure all connectors are firmly in place and seated completely.
Attach panel, with legs installed, to the connectors.

To see more check out the video below.