Hi,
To add the C1 Winforms controls to the toolbox, go to choose items and type in C1.Win into the filter bar. That will find all of the Winforms controls except for: C1.data, C1.dataextender, c1.dataexpress, c1.c1excel, c1.flash, c1.c1pdf, and c1.c1printdocument (you can skip adding those back in if you don't use them).
To add the Webforms controls, simply type c1.web into the filter bar and everything will be populated that way.