I want the first row to stay normal and then every row after that should be split into 2 columns. I've done it on Microsoft word to show exactly what I want. I tried used multicolumn but couldn't get it to work correctly.
\begin{center}
\begin{tabular}{ |c|c|c|c|c|c|c|c| }
\hline
B & B 1 & B 2 & B3 & B4 & B5 & B6 & B 7 \\
\hline
1 & 12 & 12 & 12 & 12 &12 &12& 12\\
\hline
2 & 12& 12& 12& 12&12& 12& 12\\
\hline
3 & & & & & & & \\
\hline
4 & & & & & & &\\
\hline
5 & & & & & & &\\
\hline
6 & & & & & & & \\
\hline
7 & & & & & & &\\
\hline
\end{tabular}
\end{center}




xyou can obtain with\multicolumn{2}{c}{x}. similar for others. – Zarko Mar 18 '18 at 17:10booktabspackage and following the guidelines laid out in the documentation ofbooktabsfor prettier tables. – Skillmon Mar 18 '18 at 17:55\documentclass{...}and ending with\end{document}. about tables beside what suggest @Skillmon, see https://wiert.me/2014/04/03/andre-vatter-google-wie-tabellen-eigentlich-aussehen-sollten-%EF%BB%BF/ – Zarko Mar 18 '18 at 17:58