How do I get the casters to stay in the base?

The metal stem needs to be fully inserted into the bottom of the five star base in order for the caster to stay in. There are two options. One: lay the base on the carpeted ground, with the bottom of the base facing upward. Insert each caster into the hole by applying pressure. They should pop in easily. Option two: hold the 5 star base in an upright position (One leg is on a carpeted floor). Insert each caster into the hole. Apply pressure with one hand, while using the other to hold the base in place.