こんいちわ！This can also be こにちは

こんいちわ！

わたしわはSamです。いぎりすしゅっイギリスしんです。 Do you know katakana? Imported words from other countrys are usually written in katakana, in hirigana it would be いぎりす
よろしくおねがいします。
すみませんにほんごわはちょとお。。。 ちょっと generally means "just a minute" or more like "one moment"
Did you mean to say you understand a little japanese?

すみません、にほんごはすこしわかります。　すこし meaning small amount and わかります meaning to understand.
さようなら！

The reason for this わ to は change is due to the particle "wa" being written は even though when you speak it you say wa. It is strange, i messed it up alot at first too but once you get into the language you get the hang of it and its other fun quirks ^^

はじめましてサムさん。よろしくおねがいします。わたしはピーターといいます。　

Hope this helps

がんばってください！