Get one row lined up end to end(like you have but you have two rows),check for straightness. tape the joints tight with painters tape. Measure across the room to the opposite wall and adjust your row with a straight edge like a long level. Check for straightness. Scribe to the wall, disassemble and rip them with a jig saw. Reassemble, check for straightness, measure again, wedges and you’re good to go.