"your pic shows a relay, it that the same thing as a solonoid"
"i'll probley used the starter button on the trans, but yea i was talking about useing the key ignition only"
You need to make up your mind what one you will use. This will allow us to tell you the correct parts to buy; and save me a lot of work explaining how to do it one way and then you decide to do it another.
Your tractor came with a relay (solenoid) like this
But you can use one like in your picture. The only difference is the one in my picture will allow the engine to crank (not start) without a key; the one in your picture is much better especially if you have young kids around because you must have a key to crank the engine.
My wiring diagrams use stock parts so they might not fit every way of doing a conversion. I will talk you threw any way you like.
For instance; look at this diagram from the newer tractors 1959 to 1964. It shows the relay in your picture because that is the part used stock on those tractors but it does not show the one way diode you must have because those tractors used a dash warning light.
Think about it..... Ask questions...... Decide what way you want to go and we will go from there. I wish there was a quicker way but with a whole list of parts that can be used; many that will not even work on tractors; its best if we both get on the same page before we start.
You might want to read the piece I did about 12v conversions several years ago. It may help you better understand the process.
12 volt conversions
Be For warned. I work out of a suitcase some days so it may be several days before I might answer a question. There are many here that can help you as good as I can and I know they will step in and help if needed.