As far as I know the shortcuts should work on Linux the same as windows. What are you trying to use that doesn’t work?
Yes connections are a bit picky, the best bet is to make sure the connection goes green, but clicking on a pin will light up everything that is connected to it yellow so it is a good practice to check that everything you think is connected lights up yellow if you click on a pin in the net. The other thing to note is it is best to complete one view completely then use the rats nest lines in the other views to complete them. If you make conflicting connections in two views, for example with two resistors connecting pin 1 to pin 1 in breadboard but pin 1 to pin 2 in schematic,you will cause a short across the resistor and worse Fritzing may not be able to recover the routing database even after you remove the short sometimes meaning you need to start again from scratch.
I’m not sure what you mean by test probe, but in general to find parts a google search for “fritzing part test probe” may turn up something someone else has made. If you have a data sheet for what you want , if you post a link to it I will look around. Fir the antenna there is an example for a 2.4ghz antenna here:
and I remember (but can’t immediately find) a post with 3 or 4 different directional antenna parts. Again a google search for fritzing part antenna may turn up more examples. Note Fritzing can only do 2 layer boards and some of the antennas need a 4 layer board I think.
Making parts is fairly complicated and poorly documented so you are probably best off asking for help in here (posting the part you are working on works best so we can see the xml and svg files). That said these two tutorials apply to the current version of Fritzing (most of the others are for earlier versions and may no longer apply). Old_Grey’s video series is the most complete:
Peter