Click Window and select MouseSplit.sldprt.
In the FeatureManager design tree, right-click Split1 and select Create Assembly.
In the PropertyManager, click Browse and save the assembly as AssemblySplit.sldasm.
The full path to the assembly appears for Assembly file.
Click .
Click Yes if prompted to rebuild the model.
Because the buttons were split off together from the master part, you need to replace the Buttons component with the separate buttons.
In AssemblySplit.sldasm, delete the Buttons part from the assembly.
Click Insert Components (Assembly toolbar) to insert the existing button components.
In the PropertyManager, click Browse, select LeftButton.sldprt, click Open, then .
Repeat steps 6 and 7 for the RightButton.sldprt.
Save the assembly.
In the Save Modified Documents dialog box, click Save All.