No MultiTrack Mode possible – why?

Dear Lazlo,

thank you so much for your help. I “think” I did exactly what you proposed in your step-by-step instruction. I will later create a video for you so you may see where or what I am doing wrong.
In addition I like to ask: Is there any file format requirement when using MultiTrack? Currently I am using: .wav; Mono; 44.1Khz; 24Bit Is this OK or does it have to be something else like 48Khz or 16Bit or…….?