In Path of Exile, active skill gems can give you the abilities you use in the game, but auxiliary skill gems can enhance these abilities and make them more powerful. Obtaining Support Skill Gems is easy, just like getting Active Skill Gems: Complete missions and loot from monsters. However, connecting those auxiliary skill gems with compatible active skill gems is much more complicated.
Auxiliary Skill Gems can dramatically change the way your abilities work. If your active skill gem is firing a single fireball, the auxiliary skill gem can double the effect and make it five fireballs. Another auxiliary skill gem may cause the same fireball to bleed, or increase its burning duration.
Support Skill Gem, like all POE Currency, can be used in the game to make you have strong attack power. Of course, if you are not connected to an active skill gem, the support skill gem will do nothing and will not bring any benefit. If you place the Active Skill Gem in one of the connected slots, you can increase it with any number of Support Skill Gem, depending on the number of armor or weapon slots. As long as you link the two skills correctly, Support Skill Gem will enhance the active skill gem.
You must place supporting skill gems in slots that match their colors, just like active skill gems. If you want to create the ultimate combination between supporting gems and active skill gems, you need to use a set of perfectly rolled sleeves on the gear.
Some Support Skill Gems do have limitations. For example, a bleeding Support Skill Gem may not be applied to minions who summon active skill gems. To avoid creating such poorly linked spells, be sure to read the tooltips for each Support Skill Gem before placing them. It will always inform you of features it does not support. Otherwise, even if connected, the two active skill gems cannot support each other. If you have a connection socket, try placing only one active skill gem in the group and dedicate the other connection slots to support the skill gem.
Most active skill gems are powerful themselves, but if you can skillfully link them with supporting skill gems, you can unlock the ability to destroy enemy-filled rooms. As for how to get the gems, I suggest buying them at IGGM. You don't waste time in the game and you can Buy POE Currency at a very cheap price.