こんにちはわ～ (type:konnnichiha) *This は is from the particle は and it's read わ. 

わたしはおれの今日、のネコをみたて。おれわたしのともだちをみた。

*Please remember that おれ is a very informal word for "I" though here many boys/men use it between close people. I recommend you to use わたし or ぼく. わたし is used in all situations and ぼく is used by boys/men but in the formal situation, using わたし is better. 

*今日のネコ = today's cat

*ともだちをみた = You saw your friend but you don't know if he noticed that you were there. 

ともだちにあった = You and your friend(s) saw each other = you met your friend

Good job! Please enjoy learning Japanese. I hope this helps you. 

こんにちは。

俺は今日猫をみた。俺の友達を見たSAW。俺の友達に会った（MET）。

Nice you used 俺、very masculine :) haha...

Know the difference between SAW and MET.