Help me find my way around London please

I have never been to london before and have to attend a meeting this thursday.
Can anyone tell me the best way from Euston station to the Portcullis House entrance of Westminster please ? Also a clue as to how long it would take and how much by taxi etc would be fab
TIA for any help,
Can anyone tell me the best way from Euston station to the Portcullis House entrance of Westminster please ? Also a clue as to how long it would take and how much by taxi etc would be fab

TIA for any help,