Iv just been given the CNC3-3018PrO of Santa, I cant believe i built it and downloaded all the relevant software, now im stuck and cannot for the life of me find this info 
Iv got the inventables site almost right but its asking me for information i cannot find
i.e Motion Controller, Rail size, Lead Screw, Spindle
Hope one of you more experience creators out there can help, Iv googled, U Tubed ther is nothing in the booklet that come with machine,
When you go though Easel setup it asks you those questions because the GRBL process needs certain settings that correspond to those sizes. Are you using a GRBL controller or do you have the X controller. Rail size…inventables sold a 500, 750 or 1000 mm long machine. Spindle or router are choices you would make if you bought an X carve. There are lead screw choices. All these things change the GRBL. Settings.
I guess I’d say Arduino/GRbl, 500 mm, and spindle and acme threaded rod and that should take you to the next steps. You will have to change the $ settings for your particular machine situation though.
From what I’ve read, many people use Candle to run their 3018.
Here are the GRBL settings. I would imagine you will need to change the $130, $131, and $132 for your machine travel distances and the $100 for the X, $101 for Y, and $102 for the Z axis at the minimum.
Grbl v1.1 Configuration · gnea/grbl Wiki · GitHub
Here is something I googled. It may get you closer too
My first CNC - a small 3018 chinese cheap machine (cnczone.com)
[My GRBL settings for 3018 CNC DIY machine « ejs (seniejitrakai.net)]
How to Install Candle/GRBLControl for Windows - SainSmart Resource Center
thanks so much for looking into it for me, iv give it a try and let you know how i go on, unfortunately im on 4 night shifts now so got to leave it alone till Monday afternoon