Hi,
Welcome to COL, I too am quite a newbie!
I have a 4 1/2 yr old show cocker, blue roan, Alfie.

I am so nervous letting off a lead! We live in the country and the birds, rabbits etc etc just totally get his attention and us calling him back for food, treats, toys is just a no go.
We do however go to the beach a lot through the summer and have found we can let him off on there without the panic he will run away. It is a really good place to start as you can see for miles, he does dip in the sea even when we ask him not to

but the most he chases are the seagulls - he hasn't worked out he won't catch one!
We have a 'special' ball for on the beach which he just adores! he will never go far if we have this trick up our sleeve and will just sit and look at us until it thrown.
Maybe give that a try before the distraction of all the wonderful smells you get in the fields.

Claire & Alfie