For someone that is interested in going out to fight ISIS, you must have linked up with groups in country, it would not only be useless going there with no contacts in country but quite possibly suicidal.
Currently at the time of posting this article it is NOT Illegal to go fight against ISIS in Syria, but you should look at official statements on Government/Security websites to make sure the law has not changed at time of your travel.
The Lions of Rojava suggest the below:
Before you leave, you will have a lot of questions, doubt and anxiety. This is normal. Know that once you arrive here, the situation will feel a lot better. Here are some things you can do before arriving to prepare yourself.
First you can begin language study of Kurdish by reading the Kurmanji basic book listed on that webpage. You must prepare a copy of that book, it will become a useful reference guide for you. Having a grounding in grammar when you arrive here, will allow you to more quickly pick up the language as you will simply have to learn the words (vocabulary). Grammar is more difficult to learn by yourself. This is the most important preparation you can perform. Being able to speak the language here will make you far more effective.
If you are coming here for some specific piece of work, a list of proposed projects or a proposal would be useful. Before arriving, you can do research about what you can offer and what you’d like to do, also thinking about what might be needed here. Then once you arrive here and start to better understand the situation, you can update this document and we can eventually get it translated. If you don’t have anything specific to offer, then even a cover letter explaining yourself can help for introducing you to others.
You should also study the philosophical and political origins that the movement in Rojava fights for. The main book outlining the political philosophy of Rojava is the book on Democratic Confederalism (other languages available here). You can also read the Wikipedia article, and read this BBC article by Adam Curtis.
Even if you come here to be a soldier, being here is not just about fighting. So being able to do lots of press ups or run fast, won’t put you at an advantage over someone who understands their language and philosophy.
When thinking about what gear to bring, focus on specialised items that are not commonly available. Most medicines are available here, as are common items and so on. However if you can bring those, it’s better to be prepared and self sufficient from the start. Here’s a suggested packing list we recommend:
Items highly recommended;
Good quality 6 inch boots OR with side-zips (you will take them on and off a lot)
2 pairs quality wool blend socks (OD/Blk/Tan/Grey)
2 quality moisture wicking t-shirts (OD/Blk/Tan)
2 quality moisture wicking underwear
Web belt (BDU, Riggers)
Wrap-up waterproof rain cover (full body)
Hat, Gloves, Layer-Wear, Thermal Underwear and Jacket depending on when you are in country (refer to weather section)
Watch with alarm
Hiking Pack (100 L) You will have to hike it for 5-8 hours
Day Pack/Patrol Pack
First Aid Kit (mountable on belt, plate carrier or LBV)
Multi-Tool or Swiss Army knife
Flashlight (powered by AA batteries)
Compact Binoculars (ideally 12x)
2 quality toothbrushes
Razor handle with refills
Pocket lazer range finder
Water filter / tablets kit if easily affected by water
Knee pads / elbow pads
Body Armour – despite YPG not wearing it. Check with your local authorities if you can transport it. You can also buy cheap BA in your arrival city, but you get what you pay for.
EBook reader or MP3 player
Notepad and pen for writing Kurdish words.
For electronics, everything here uses the European style double pin socket but often other socket styles can be found.
For the airport, make sure you have a good cover story which explains why you’re travelling to this region. Just make sure everything is consistent with your own experience and history. That it sounds plausible.