User owner's manual Grundig T55-732/5 text

Dear......

My father in-law who has died used to own a classic 14" Tv Model T 20-6210/6, with a remote control Model TP 711, when I switch it ON a Key with 4 stars shows up, I tried few numbers including 0000, but unfortunatly no luck,
pls. advice for the following:
1 - what is the (manufacturer) original password (key password)
2 - If I need to reset it where is that and how
3 - I need to reprogram the TV how is that

Knowing that :
- I do not know german language and I have been adviced by Grundig main site to download from Buchproduktion.......
Many thanks in advance
Eng. Nazir Touma (Lebanon)