Hi giro,
Setting the forks to Kinematic is correct, but perhaps there is an issue with the base vehicle movement. Probably the best way to make sure that the forklift is still drivable after you add the fork movement is to make sure that your Blueprint setup for the forklift is similar to the default Sedan in the Vehicle Template. Then add in the additional movement for the Forks. Check your Blueprint against the one used for the Sedan and then follow the steps below to add in the fork movement.
Start by creating a Button Press with a Timeline and set a custom float Variable in the vehicles EventGraph.
Then create a Float Track in the Timeline.
