There are softwares that can be used for this purpose. you can assemble your contigs to get whole genome sequence. Seqman of DNA star is one of them. there are other online software too that can be used.
It depends on what kind of data you have. To order your contigs and reconstruct a pseudomolecule representing your chromosomes you need information such as jumping libraries and/or long sequencing reads. With that you can use a software package such as SSPACE or SOPRA to create scaffolds and perhaps a complete pseudomolecule. Some of the current short read assemblers have the option to produce scaffolds from "just" paired-end short reads. If you do not have any additional data it would be difficult, when not impossible, to close/finish de genome sequence.