Welcome! As @Zed says , ratchet straps for compressing the struts. Its worth checking that you have the struts which have removable pins locking the springs in. My Devon poptop from about late 1974/ early 1975 has swaged struts that mean the springs can not be removed simply . I had to cut and re weld the strut tubes to fit new springs, making a jig to hold it all together while I welded it.