You can refer to this:
Commonly Used Terms In DN
Although the guide is kinda old but most of the terms we are still using. Except the Nests and Sets sections. (The equipment was 70cap equipment and back when the day there are many low level nests but they were removed for future purpose)
pt = party [party with the others who are LFM(Looking for members) or LFP (Looking for party)]
rh = Returned Hero, there are players with blue title Returned Hero (they were inactive for more than 1 month without login their id). They have the bonus drop rate and exp rate which can help themselves and their party members to gain exp and up level faster. (There are other welcome back gifts for them RH if you need more information, visit 1.2k Mark - DNSEA)
pledge costume = guild costume where you buy the costume for set effect which you can gain up to 20% bonus exp, along with 2% bonus hp and physical/magical attack. A level 24 guild will be sufficient to provide you a full set for purchase. (Yes, buy, should be less than 100g total for full set unless my memory fails)
As Garand suggested that you may grind some dungeons with faster clear time repeatly to gain level fast enough. (There are some guides out there for power leveling / boosting, you may take a look at Guide & Strategies section)
However, I will suggest a completely new player to do main quests and side quests as they give a fair amount of money for you to repairs or enhance your future max level equipment. Also, enjoy the story (though I have never really read them )
It's quite easy to get into a guild, you can just apply and wait for them to accept you through guild UI or when you see they are shouting or using bluebird in world channel to recruit member, just pm them. As long as you are active, there are lots of guilds willing to accept you. (Our guild is one of them, they usually use acronym. E.g. RGM>Servinity, recruiting guild members). There are many benefits for joining a guild. So make sure you join one and befriend with guildies.
In case if you don't have any guild in mind, you can click my signature for our guild information. We are a cross server guild, so we have a GwWw branch there too even though you aren't gonna meet me there, there are our friendly guildies ready to assist you.
Lastly, the character you have drawn for me is my Destroyer (destro for short) and they call me Ecchi/Pervy. So you drew pervy's destro. That's what he meant.