I often hear these mistakes made by German speakers who are learning English.
They say: On work days I usually stand up at 6.30 a.m. If it’s not a work day, I sleep longer and normally stand up at 8 a.m.
This is totally understandable but it is incorrect. ‘Stand up’ is not correct here. We can stand up from a sitting position (in a chair for example) but when getting out of bed we use the verb to get up.
Correction: On work days I usually get up at 6.30 a.m. If it’s not a work day, I sleep longer and normally get up at 8 a.m.
Have fun learning English!
Louise