I don't know how to switch tone

can someone help me?

Tone changes are placed (on a per-track basis) by seeking to the desired part of the chart (ie. at/before where the different guitar part comes in) and using "Track>Rocksmith>Tone change>Add". You can use the "List" function in that menu to get an overview of where all the tone changes currently are. Also make sure to go into the "Names" function to see a list of all the tone changes in use to verify none of them are mis-spelled (If you have one called "solo" and one calld "soloo" they will be treated as different tones) and to make one of them the default (the one in effect automatically when the song begins).

Thank you