First we start with the bare pcb:
There can be some ridges on the pcb. We need remove them before assembly.
On the picture above you see the first step for soldering the JFETs (MMBF-J201). One pad per JFET gets coated with solder. Now you take a JFET with tweezers and place and fix it on the corresponding place. Heat up the pad (you coated before) and pin (of the JFET) to get a joint.
ATTENTION: JETs are very sensitive for heat and ESD. This step is the most crucial step in the whole instruction. Take care and take your time.