Note: this article is about the tellytubbbys involvement in the war, for more information on the conflict as a whole see: wookieepedia/the clone wars
It all began when about 1 year into the war when the tellytubbys had to pick a side they chose the republic over the confederacy of independant systems (CIS)
then when the tellytubbys realized the republic could no longer protect them they began the kanwattt armouring (in which tellytubbys first obtained guns)
and then they joined the confederacy of independant systems. The republic was not happy.