Congratulations on the new scope!
That is fine optical instrument you have there. I have a dear friend who also gave me mine many, many years ago... It is true you can attach an SCT 2" diagonal, and I have, but it is such a small wide field scope, I just felt it was not needed. You can easily attach a 1.25" diagonal and be ready to view (see first photo). Another thing I like about this scope that the foot has the ability to be attached to a photo-tripod, but also has the shape and dimensions of a Vixen dovetail, one of the more popular attachment methods to an astronomical mount. What you also have is the 0.8x focal reducer/field flattner, in all intents and purposes it is rarely used for visual observing, but is very important for astrophotography with a large sensor camera (DSLR). The 0.8x FR/FF also has the SCT threads and the blue ring can be screwed off and the flattner screwed on. After that, you can screw a T-mount or T-ring to the flattner and attach a DSLR or other dedicated imaging camera, very desirable with this scope. I have not used mine in years, but when I started AP, this was my most used scope as it have such a wide field and can easily be used unguided.
If it were me, I'd talk to your friend about a diagonal and maybe an eyepiece or two (that's a whole other conversation with MANY opinions on these forums) the 20mm SWAN eyepiece will only give you ~20x magnification, planetary details may be difficult. This scope excels at sweeping the Milky Way, star fields and clusters, the Pleiades are outstanding with this scope.
With 1.25" diagonal
Attaching 0.8x FR/FF (mine is a different version, but they do the same thing)
Attaching camera (there is you can see the T-ring between the FR/FF and DSLR)
All set up for AP (I rotated the focuser upside down for easy access to the focuser lock and I also mount this side by side with another scope)