What he said^.
With all due respect, the fact that you're asking about how a receiver sight is installed points to you using the services of a real gunsmith (not some AR parts-changer) to install it on the Mauser.
The receiver sights designated for the Mauser fit on the RH side of the receiver bridge, just ahead of the bolt handle, and would need two holes placed there (if it's not already so prepped), drilled & tapped for 6-48 sight mounting screws.
The actions of Mauser rifles are surface case-hardened, and need the proper tools to drill & tap (D&T), a guiding fixture to properly position the holes being drilled, and spot annealing of the action where the holes are to be drilled (to allow trouble-free D&T).
If precision is desired, I would suggest choosing a receiver peepsight that has micrometer/click windage & elevation adjustments (low or no protruding adjustment turrets if the rifle's to be used for hunting).
Husqvarna's are among the best made Mauser-pattern rifles you can get - enjoy it !
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