How to create supports for the parts hanging above 45 degrees?
PrusaSlicer has support enforcers you can place on areas that need support.
See this video: Prusa Slicer Support Enforcers.
Automatic supports
There are automatic supports, in the Supports dropdown menu, select Everywhere:

Click Yes in the resulting dialog:

Click on the Slice icon in the bottom left:

You will end up with a lot of supports:

However, this method generally results in too much support...
Custom Suport Enforcers
So turn off Supports in the drop down menu, select None:

Now, in the Print Settings tab, under Support Material, disable Auto Generated Supports and enable Generate Support Material:

Then right click on the model and select Box from the Add Support Enforcer menu item:

You can move by clicking the Move button in the left hand palette,

resize by clicking the Resize button

and re-shape the Box as necessary, to support the difficult overhanging parts parts only. Here we can see three boxes have been added - pale blue for the previously added boxes and green for the current box:

And a fourth final Box for the tail:

Now, when you hit the Slice button, there will be much less support structure than when using Automatic supports:

Parts of the model that the slicer thinks still needs support will be highlighted in dark blue (such as the elbow and back of the head):

Add a cylinder support enforcer:

Resize and re-shape as before and move into position below the elbow:

Adding a second cylinder as a support enforcer

Upon hitting Slice:

Now in Print Settings - Support Material - Pattern change it from Rectilinear to Rectilinear Grid:

For prints with curves and details Rectilinear Grid works better, than Rectilinear (which is fine for supporting a plain cube in the air). It is easier to break the support off the print.
Now save your hard work as an AMF file:

This file maintains all of the support enforcers so that they can be modified if the actual print needs some adjustments - without having to re-add all of the support enforcers all over again.