Failed at making cave, won at making Tunnel

God damn it ! I tried over 500 times to make cave but i am failing somehow, at last step it just changes to tunnel o_O or glitches. If anyone would mind providing me with link to any tutorial about making caves then i probably may find out what i’ve screwed.

i’ve googled for tutorials but all i found were presentations of already done caves >.<

Take your tunnel, ensure all your interior brush faces are quadrilaterals, displace + sew.

Err… failed, it looks now like hole in the ground errr…

Perhaps with some pictures and such as to exactly what the problem is we might be able to help you better.

See: right side of picture

After subdivision:

Ahh i know it but seems like i choosed one face more and it just went over whole entrance XDD Sorry guys also thank u !

Urgh… Wut?

Ehhh, look kind of fail?