It can be very intimidating to get started. One of the first things you are going to want to do is unlock all of the basic machines. If you want to go for usefulness first,
Grind Stone - Turns Cobble into Gravel
Automated Panning Machine - Turns Gravel into Sifted Ore (And 3 other byproducts)
Ore Washer - Turns Sifted Ore into 9 different dusts (The foundations of slimefun)
Smeltery - Turns dusts into ingots
Along the way you also need to unlock in the "basic resources" section of slimefun all of the dust types (Iron, Gold, Copper, Tin, Silver, Lead, Aluminum, Zinc, Magnesium) and every ingot type as well. Eventually you want every single basic machine and basic resource unlocked. These should be the first things you unlock in slimefun.
If you want to reach automation, there are a lot of other things you need to build first. A mining android is always my first goal when starting fresh in slimefun, and in order to build one we need a lot of different parts. Luckily in slimefun, clicking on a part tells you what you need to build the part. For example, a mining android needs 2 diamond pickaxes, an electric motor, and a programmable android. if you click on the electric motor you can see what you need to build it. Copper Wire and Electromagnets. If you click on the copper wire, it will tell you you need 3 copper ingots in a row in an enhanced crafting table to make 8 copper wire.
The real major hurdle of androids is plastic sheets. To get these, you need to build a satellite at the highest Y level you can. Pillar up to make a small platform. You then need to place an Energy Regulator, 2x GPS transmitters, 2x Basic Solar Panels, and a small energy capacitor. On the ground afterwards you need 1x Energy Regulator, a GPS control Panel, a GPS Geo-Scanner, and finally if the chunk you geo-scan has any oil in it, an oil pump.
Once you have buckets of oil, you then need to build a heated pressure chamber so you can turn the oil buckets into plastic sheets. Once you finish, you can build a basic android and upgrade it to a basic mining android. Basic Mining androids use various fuels which are listed on their slimefun page, but I usually use blaze rods since they last 45 seconds, and blaze rods are relatively easy to get.
Set up your mining android in front of a cobblestone generator with an android interface (fuel) on the left and android interface (items) on the right, open your android and then click on memory core, click download a script, and download cobble miner by Onigob. Then put a few blaze rods into the fuel section of your android and click the start/continue button and your mining android will start auto mining.
Once you get this far, you're semi-auto. You still have to pull out cobble and put in blaze rods. The next steps are probably going to be automating this. Build a pickaxe of containment, get some blaze spawners from the nether, build an ancient altar, make all the runes you need to and all the components to fix the spawner, then put the spawner down in a basic spawner mob farm formation, then build a butcher android to kill the blazes.
After that, you need to set up a basic cargo network to send the blaze rods to the fuel inputs for all of the androids.
All this stuff is just to automate resources. If you can make it this far, you can pretty much automate anything by running enough things through enough machines or setting up various ways to kill things.