Here's my problem:
I want to create tables that span multiple pages. If I understood it correctly I better have to use longtable for this.
I need 6 columns and each column should be the same fixed width. (The table should span the entire page width expect for its margin)
How do I do it? Keep it simple please, I have little to no experience in working with LaTeX
For tables with fixed width columns I would prefer using the tabu package that offers longtabu which can spread over multiple pages.
The following MWE creates such a table.
With {X[c]X[r]X[l]X[c]X[c]X[c]} you can specify the amount of colums you want to use and their format. X stands for a column that is as wide as it has to be to fill the desired width (default is textwidth). If there is more than 1 X-column, every X column gets the same width. [c], [l] and [r] are the usual possibilities to set centeres, left-aligned and right-aligned text respectively.
As you can see from the example, longer entries are automatically spread over multiple lines and a caption can be added inside the longtabu environment.
\documentclass{scrreprt}
\usepackage{longtable}
\usepackage{tabu}
\begin{document}
\begin{longtabu}{X[c]X[r]X[l]X[c]X[c]X[c]}
column 1 & column 2 & column 3 & column 4 & column 5 & column 6 \\
\hline
\endhead%
a longer entry & b & c & d & e & f \\
g & h & i & j & k & l \\
m & n & o & p & q & r \\
s & t & u & v & w & x \\
a & b & c & d & e & f \\
g & h & i & j & k & l \\
m & n & o & p & q & r \\
s & t & u & v & w & x \\
a & b & c & d & e & f \\
g & h & i & j & k & l \\
m & n & o & p & q & r \\
s & t & u & v & w & x \\
a & b & c & d & e & f \\
g & h & i & j & k & l \\
m & n & o & p & q & r \\
s & t & u & v & w & x \\
a & b & c & d & e & f \\
g & h & i & j & k & l \\
m & n & o & p & q & r \\
s & t & u & v & w & x \\
a & b & c & d & e & f \\
g & h & i & j & k & l \\
m & n & o & p & q & r \\
s & t & u & v & w & x \\
a & b & c & d & e & f \\
g & h & i & j & k & l \\
m & n & o & p & q & r \\
s & t & u & v & w & x \\
a & b & c & d & e & f \\
g & h & i & j & k & l \\
m & n & o & p & q & r \\
s & t & u & v & w & x \\
a & b & c & d & e & f \\
g & h & i & j & k & l \\
m & n & o & p & q & r \\
s & t & u & v & w & x \\
a & b & c & d & e & f \\
g & h & i & j & k & l \\
m & n & o & p & q & r \\
s & t & u & v & w & x \\
a & b & c & d & e & f \\
g & h & i & j & k & l \\
m & n & o & p & q & r \\
s & t & u & v & w & x \\
a & b & c & d & e & f \\
g & h & i & j & k & l \\
m & n & o & p & q & r \\
s & t & u & v & w & x \\
a & b & c & d & e & f \\
g & h & i & j & k & l \\
m & n & o & p & q & r \\
s & t & u & v & w & x \\
\caption{caption}
\end{longtabu}%
\end{document}
For an overview of available packages for tables and a short description, please refer to this answer.
