This is a 3d printed robot design that you can build. The you tube video shows how to assemble the robot. It is based on a very old leverage push rod design called by toy robot collectors as a Pin Walker. Toy robots like Lilliput robot from the 1930's and Atomic Robot Man from the 1940's both used this type mechanics. Also my Drone robot #5 Rocky that you build uses this type of mechanics.
I have added a Motor Small Gear "NEW" STL file. it has the D slot going all the way threw the gear so that the small motor drive gear can slip all the way on the motor shaft even if you use a different gear motor than I did.
I did not require any radfts or supports on the parts except for the arm levers, they required supports.